Underfeed-stoker.



PATENTED JUNE 20, 1905.

a SHEETS-SHEET 1.

E. B. TAYLOR. NDERPEED STOKER.

APPLICATION FILED 1330.8, 1904.

No. 792,862. PATENTED JUNE 20, 1905. E. 'E. TAYLOR.

UNDERFEED STOKER.

APPLICATION FILED DBO. 8, 1904 '3 SHEETS-SHEET 2.

No. 792,862. PATENTED JUNE 20, 1905. E. E. TAYLOR.

UNDBRFEED STOKER.

APPLICATION FILED DEO. 8, 1904 3 SHEETS-SHEET 3.

NITED STATES Patented June 20, 1905.

E LVVOOD E. TAYLOR, OF BOSTON, MASSACHUSETTS.

UNDERFEED-STOKER.

SPECIFICATION forming part of Letters Patent No. 792,862, dated June 20, 1905.

Application filed December 8, 1904. Serial No. 235,993.

To all whom, it may concern.-

Be it known that I, ELwooD E. TAYLOR, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Underfeed-Stokers, of which the following is a specification.

This invention relates to mechanical stokers operating to feed the fuel beneath the fire, and especially to stokers of the character shown and described in the patent granted to me December 27, 1904, No. 778,812.

The objects of the present invention are to provide an apparatus of the kind illustrated in said patent having an improved mechanism for feeding the fuel into the retorts directly toward the rear of the fire-box, which is capable of adjustment, so that all the fuel may be fed in either at the upper or the lower part of the retort-mouth, or fuel in varying proportions may be fed at top and bottom simultaneously, and to provide an improved construction of air-supplying twyers, thereby obtaining the advantages hereinafter set forth.

The invention consists in an underfeed mechanical stoker having the novel features and improvements which I will now proceed to describe and claim.

Of the accompanying drawings, Figure 1 represents a vertical longitudinal section of a furnace provided with my improved stoker. Fig. 2 represents a horizontal section on line 2 2 of Fig. 1 with parts of the apparatus shown in plan, the bridge-wall being omitted. Fig. 3 represents a front elevation. Fig. 4 represents a side elevation of two of the twyerblocks in the relative position they occupy when in place, one of the twyer-blocks being shown partially in section. Fig. 5 represents an under plan view of one of the twyer-blocks. Fig. 6 represents a detail sectional view on line 6 6 of Fig. 1 looking in the direction of the arrow.

The same reference characters indicate the same parts in all the figures.

In the drawings, 10 is the furnace-inclosure, 11 the bridge-wall, and 12 the front wall provided with a fire-opening 13 and adoor 14 for introducing kindling, &c., to start the lire.

15 15 are fuel-feeding retorts arranged in series in the same lateral zone and having their mouths formed with a slope downward from the front toward the rear of the furnace, the structure being similar to that of my patent above referred to. Between the retorts are air-supplying boxes to which are connected at their outlet ends the twyer-blocks 16, the latter being formed with converging sides, so that each block is approximately wedgeshaped in plan view, and these blocks being superposed upon each other in the manner shown in the drawings constitute inclined ridges, which separate the retorts from each other.

The fuel is placed in a hopper 20, which may be formed as a single hopper extending the Whole width of the furnace and having connecting branches 21 leading to the several retorts, the fuel being led into the hopper in any desired way,as by means of a chute 201, leading from an overhead bin. From the branches 21 of the hopper the fuel is pushed into the retorts by means of reciprocating plungers or pushers 22 and 23, the pushers being mounted in line with each of the retorts. These plungers or pushers are preferably, though not necessarily, cylindrical and of a diameter substantially equal to the width of the retorts. They may also be rectangular or of other outline in crosssection; but whatever form may be given to them their widths and heights will be practically equal. The pusher 22 is arranged to reciprocate in a path extending substantially horizontally toward the rear of the furnace and in line with the upper part of the retort, while the other pusher 23 is in line with the lower part of the retort, this arrangement being provided for the pushers connected with each of the retorts. The pushers are reciprocated by means of a shaft 24, extending across the front of the furnace and having cranks 25, each of which is connected to a connectingrod 26, attached by a wrist pin 27 to the pusher 22. The shaft is rotated by any suitable mechanism. From the connecting-rod 26 there is extended an arm 30, which projects downwardly and has its lower end formed as a fork extending over a rod 31, pivoted at to the lower pusher 23. Adjustable collars 37 and 38 are mounted upon the rod 31 on each side of the arm 30 in position to be engaged thereby as the latter and the connecting-rod 26 reciprocate. The arm 30 may be attached to the connecting-rod at any point; but I prefer to form the connecting-rod as a bell-crank lever, the arm 30 thereby forming one of the arms of the bell-crank and extending downward from the point 27, where the connecting-rod is attached to the pusher 22.

It is possible to attach the arm 30, which actuates the lower pusher, directly to the pusher 22; but with such a construction the resistance of the lower pusher, being applied to the upper pusher at a different point from that at which the connecting-rod is attached, tends to turn the upper pusher in its guideway and cause it to cramp therein, increasing its resistance and tending to break the arm or the connecting-rod. With the construction shown, however, where the resultant of all the actuating and resisting forces is applied at a single point, all the resistance of the pusher 23 is taken directly by the connecting rod, while the upper plunger acts simply as a guide for the elbow of said connecting-rod and is free to slide easily, there being no tendency to twist it out of line with its guide and cause it to bind therein.

By shifting the position of the collar 37 the throw of the pusher 23 may be varied from nothing to the full amount of travel of the upper pusher 22, so that, as desired, the lower pusher may be caused to remain stationary or to have any amount of travel within the limits of the throw of the crank. When the parts are in the position shown in Fig. 1, the fuel will fall through the connection 21 in front of the pusher 22 and will be forced rearward as the latter advances into the passage 39, leading to the upper portion of the retort 15. If the adjustment ofthe collar 37 is such that no motion is given to the lower pusher,

the fuel fed by the upper pusher will drop into the lower part of the retort behind the lower pusher until the retort is filled up, after which subsequent reciprocations of the upper pusher will force the freshly-supplied fuel into the upper part of the retort, and all of the green fuel will thus be fed to the upper portion of the bed of fuel in the retort. If, however, the adjustment of the collar 37 is such that the travel of both pushers is equal, the fuel fed by the advance of the upper pusher will be supported by. the lower pusher until the latter is retracted, when the charge last fed will drop into the space at the rear of the lower pusher and will be fed by that pusher to the rearin the lower part of the retort on its next advancing stroke. Thus the entire feed of fuel will be to the bottom portion of the bed of fuel at the rear of the retort. By setting the collar 37 atan intermediate position, however, so that the lower pusher is given an amount of travel less than that of the upper pusher, fuel may be varied to any desired degree by varying the adjustment of the actuator for the lower plunger, and thereby varying its travel. Thus the upper surface of the fuel-bed may be made either horizontal or be given a slope of any desired degree up to the angle at which the material will slide.

Of course it is to be understood that all the fuel fed into the retort is first introduced through the passage 21 into the upper portion ofthe retort; but from this point thefuel is fed to the bed of fuel in the rear of the retort in the ways above described. By fuelbed or bed of fuel is meant the surface of the fuel in the rear and upper part of the fire-box or furnace inclosure into which the retorts open which is ignited or which is becoming coked preparatory to being ignited.

At the rear of the furnace, adjacent to the lower and rearward ends of the retorts, are pivoted dumpinggrates 36, of which there may be one in line with each of the retorts, or a single grate may be provided to extend across the entire width of the furnace. These grates consist of rectangular open metal frames having journaled in opposite sides the grate-bars 56, having the intermeshing fingers 57, and the frames themselves are journaled at 2 adjacent the rear ends of the retorts. They may be rotated to dump the ashes or fuel supported by them by means of the linkage consisting of links 40 and 58, bellcrank 59, and lever 11. Any desired means for operating the lever 41 may he used-as, for instance, a rock-shaft extending across the front of the furnace having a separable clutch connection with each of the levers 41 and means for oscillating the rock-shaft. One or more of the grate-bars of each grate has an arm extending downwardly curved on the arc of a circle whose center is the pivot 42 and engaged by a forked arm 61, (see Fig. 6,) mounted on a rock-shaft 62, which extends from front to rear of the furnace, there being one under each retort. In case several gratebars are mounted in one frame, as shown in the drawings, only one of such grate-bars being connected to be rocked, the other gratebars may be held stationary in the frame by any suitable means. Each rock-shaft has at its forward end an arm 63, several of the arms being connected together and to an operatinglever by links 64:. By oscillating the lever 65 the arms 60, and thereby the grate-bars 56, are oscillated also to shake down the ashes and break up whatever clinker may form or lodge on the grates. The curved form of the arm 60 allows it to remain in engagement with the arm 61 while the frame is being turned to dump the grate. The grate-bars may be frequently shaken to break up the fuel and clear thorough cleaning to the fire or to remove the refuse too big to pass between the grate-bars.

Air is fed through a pipe 43 to an air-trunk 44, extending across the furnace beneath the retorts and communicating with the air-boxes 45 between the retorts. A wall 49 of the trunk and a plate 50, having brackets, form supports to which footings on the air-boxes may be bolted to secure the latter in place. Openings 501 are made through the plate 50 to permit the air to fiow freely through from one part of the air-trunk to the other. Horizontal plates 51 52, Fig. 1, extend over the air-trunk and form the bottoms of the retorts, while plates 53, Fig. 2, between the plates 52 cover the portions of the air-trunk at the rear of the open ends of the air-boxes and support the twyer-blocks.

The air boxes are formed with parallel straight sides and sloping outlets having the same inclination as that of the retort-mouths, and closing the outlets to the said boxes are the angular twyer-blocks 16,which have openings 32 in their lateral faces and passages leading thereto and communicating with the interior of the air-boxes. Thus the retorts, which are bounded by the air boxes and twyer-blocks, are formed with parallel vertical side walls extending up to the point at which air is admitted from the twyers, above which point they flare outwardly and merge with the adjacent retorts. The shape of the twyer-blocks is shown in Fig. 5, which shows an under plan view of one such block. Its interior is cored out and formed with ribs between which are passages leading from the wide end of the block, which is adapted to be placed adjacent the open end of an air-box, to the openings 32 in its side faces and to a chamber 54 in its apex, which is provided for the purpose of admitting cool air to the point of the twyer to prevent its being burned off. The lowermost one of each set of twyer-blocks rests upon one of the plates 53, covering the air-trunk between two adjacent retorts, while the remaining blocks are superposed upon it and upon each other, each block having a lug &6 on its bottom near the apex, which projects into a socket 47 in the upper surface of the next lower block, and a projection or wing -18, adapted. to extend into the opening of the air-boxes and hold the twyer-blocks in proper position relatively to said boxes and to each other.. By reason of this arrangement of the twyer-blocks the heat is directed only on their sides and no direct heat strikes their broad flat surfaces, whereby'injury from warping is avoided. I

By constructing the twyer-blocks with the shape hereinbefore described the fuel is permitted to spread out from each of the retorts and come in contact with that fed through the other retorts to form a single wide bed of fuel extending across the whole extent of the furnace, the fuel in the retorts constituting legs which support the burning fuel-bed and supply green fuel, which becomes coked as it is being forced out to the surface of the fuelbed and before it reaches the ignited portion of the bed. The feed presses the burning fuel directly backward, and by the time it reaches the bridge-wall practically all the combustible material is consumed, and the matter resting on the dumping-grates consists only of ash and clinker when the feed is slow. This can be removed from time to time after a suflicient quantity has accumulated by tilting the grates or by shaking the grate-bars.

By constructing my furnace with the dumping-grates at the rear thereof and the wedgeshaped twyer-blocks between the retorts I am enabled to avoid the necessity of having.

flat dead-plates between the retorts upon which the ash may collect and which, to the best of my knowledge, is necessary in all the other types of underfeed-stoker now in use. Thus I am enabled to have a bed of burning fuel extending completely across the whole extent of the furnace instead of one having zones of hot fuel alternating with Zones of dead ash, and thereby a greater quantity of fuel may be burned with greater economy by my apparatus than with any other. Further, in order to burn the same amount of fuel with a furnace having dead-plates between the retorts it is necessary to force the fire harder and supply more air with a consequently decreased eificiency of burning than is the case with my invention. The pushers at the same time that they feed the fuel break up the lumps formed by the coking of the green fuel, and thus keep the fire well sliced and avoid the necessity of breaking up the lumps by hand manipulation. It will thus be seen that by my invention I have produced an apparatus by which a perfectly clean lire of any desired degree of intensity may be maintained without any attention other than that of an occasional dumping of the ashes, which may be accomplished by a single manipulation of the lever 41.

It will now be understood that the fuel is coked in the inclined retorts 15 and that the twyer-blocks 16 constitute grated surfaces which provide for the supply of air from the air-boxes t5 between the retorts. The burning fuel-bed will therefore be in the plane of said grated surfaces and will be to some extent supported thereby. The upper and lower pushers, one of which may be given a greater amount of travel or range of reciprocation than the other, serve to supply the fuel from the retorts to the upper and lower portions of the burning fuel-bed in just the proper quantities to keep said bed properly supplied and sliced according to the grade or kind of fuel used.

I claim 1. An underfeed mechanical stoker comprising an inclined fuel-retort in which the fuel is coked, grated surfaces arranged to supply air to fuel from said retort, means for feeding fuel to the upper end of the retort, upper and lower means for pushing fuel in the retort toward the plane of the said grated surfaces, and means whereby one pusher may be given a greater amount of travel than the other.

2. An underfeed mechanical stoker comprising an inclined fuel-retort in which the fuel is coked, grated surfaces arranged to supply air to fuel from said retort, means for feeding fuel to the upper end of the retort, upper and lower means for pushing fuel in the retort toward the plane of the said grated surfaces, and adjustable means for regulating the action of one fuel-pushing means with respect to the other.

3. An underfeed mechanical stoker comprising a retort having a sloping mouth longest in a direction up and down the slope thereof, and means for feeding the fuel through said retort from the front thereof across the plane of said mouth, means for varying the feed in the lower portion of the retort relatively to the feed in the upper portion of the retort.

4:. An underfeed mechanical stoker comprising a plurality of retorts arranged side by side in the same lateral zone and adapted to support a single fuel-bed, air-supplying means at the sides of the several retorts, said retorts and airsupplying means alternating in a horizontal direction, upper and lower means for pushing fuel in the retort toward the plane of the said air-supplying means, and means for regulating the action of one fuel-pushing means with re spect to the other.

5. An underfeed-Stoker comprising a fuelsupport, means for feeding green fuel beneath the bed of fuel thereon, a dumping-grate consisting of a frame pivoted adjacent one ofits sides at the rear end of said fuel-support, and a grate-bar pivotally mounted in the frame perpendicular to the axis thereof, means connected to the frame for turning the same about its pivot to dump the grate, and means for oscillating the grate-bar comprising an arm extending from said bar and curved on the arc of a circle concentric with the pivot of the frame, an oscillatable shaft, and aforked arm carried by the shaft embracing a portion of said first-named arm.

6. In a furnace, a fire-box having a plurality of retorts, air-boxes between adjacent retorts, reciprocating pushers located one above and forward of the other in the front portion of each retort, means for feeding fuel in the rear of the upper pusher, mechanism for reciprocating the upper pusher comprising a crank and a connecting-rod attached to the said pusher, an arm extending down ward from the connecting-rod, a rod pivotally connected to the lower plunger and having a sliding engagement with said arm, and stops mounted on said rod on opposite sides of the arm.

7. In a furnace, a fire-box having a plurality of retorts, air-boxes between adjacent retorts, reciprocating pushers located one above and forward of the other in the front portion of each retort, means for feeding fuel in the M A. C. RATIGAN, O. F. BROWN. 

